Expressed sequence tags (ESTs) with 300 to 500 base gene fragments, represent about only 10 to 30% of the average cDNA. cDNA is a laboratory synthesized DNA that contains only exons in their fragment. These allow the genetic researchers to limit their research to only information containing gene fragments.
Patenting of gene fragments has sparked controversy. This is because researchers feel that allowing many patents on gene fragments of same genome adds up to costs to the researcher who is interested in examining the whole genome. The researcher will not only have to pay to each patent holder in order to get an opportunity to study each gene fragment, the researcher will also have to pay the people he has hired to study different patented genes and determine which genes are applicable for his research.
Variation in DNA sequences when a single nucleotide in the gene is altered is known as single nucleotide polymorphism (SNPs). For instance, SNP might alter a DNA sequence GATCAATA to GAACAATA. Along the human genome, SNPs occur after every 100 to 1000 bases. They can occur in both coding part of the gene as well as non-coding part of the gene. Normally, SNPs have no affect on function of cells, but researchers believe that some SNPs can make people more likely to contract a disease or affect their response to a drug.
Difference in genomic sequences influences how humans respond to different diseas ...